Facile one‐pot, three‐component synthesis of novel bis(heterocycles) incorporating thieno[2,3‐b]thiophenes via Michael addition reaction

Abstract

AbstractA synthesis of novel series of bis(2‐amino‐3‐cyano‐4H‐chromene), bis(2‐amino‐3‐cyanopyrano[3,2‐c]chromene), bis(6‐amino‐5‐cyano‐1,4‐dihydropyrano[2,3‐c]pyrazole), and bis(2,7‐diamino‐3,4,6‐tricyanopyrazolo[1,5‐a]pyridine) derivatives linked to thieno[2,3‐b]thiophene core via ether or ester linkages was reported. The formation of the target compounds presumably proceeds through a three component reaction of the appropriate bis(aldehyde) with 2 M of each of malononitrile and the corresponding active methylene compounds namely; dimedone, 4‐hydroxycoumarine, 5‐methyl‐2,4‐dihydro‐3H‐pyrazol‐3‐one, or cyanomethylpyrazole in dioxane at reflux in the presence of piperdine as a basic catalyst. The chemical structures of the new compounds were elucidated by several spectral tools.